Visual dominance in inhibitory conditioning in the pigeon

In a conditioned inhibition paradigm (A+, B+, AX?_, pigeons received either of two keylight stimuli reliably followed by food (A+, B+). However, when one of these keylights was accompanied by another stimulus, food did not follow (AX?). For some groups, the putative inhibitor was a tone, whereas for others it was illumination of a red houselight. The birds pecked the A and B stimuli at a high rate. When X was red houselight, the birds pecked A at a much lower rate in the presence of X. When X was a tone, discrimination between A and AX was much poorer. Moreover, in a transfer test, red houselight inhibited responding to the other keylight, B, but tone did not. These results indicate that red houselight becomes a conditioned inhibitor more quickly than tone in appetitive situations, just as red houselight becomes a conditioned excitor more quickly in those situations. These results contradict the assertion that the latter outcome occurs because red houselight is a stronger appetitive excitor than tone at the start of the experiment (the “head start” hypothesis).     

Representation and retention of three-event sequences in pigeons

The present experiments studied a three-event delayed sequence-discrimination (DSD) task: one arrangement (order) of two stimuli (red and yellow overhead lights) taken three in succession (e.g., red, yellow, red) was the positive sequence and the remaining seven arrangements were the negative sequences for responding and reward during the subsequent test stimulus. In Experiment 1, the final stimulus (recency) and the order of stimuli in the positive sequence controlled acquisition of discrimination. In Experiment 2, increasing the duration of memory intervals between stimuli reduced the discriminability of those negative sequences identical to the positive sequence after the delay. Three-event DSD performance in Experiments 1 and 2 was similar to two-event DSD performance in comparable published experiments. Models developed to explain pigeon performance in two-event DSD were extended to the three-event task. Results from both two- and three-event versions of the DSD task falsified a noncumulative model and several cumulative integration models (i.e., adding, averging, and some multiplying models), but corroborated one cumulative, multiplying model.     

Induction of depressive affect after prolonged exposure to a mildly depressed individual

Scores on the Beck Depression Inventory (BDI) were periodically obtained from the roommates of college students who exhibited a persistent mild depression over a 3-month period. For comparative purposes, BDI scores were also obtained from roommates of individuals who were transiently depressed and from subjects with nondepressed roommates. In comparison with control subjects, the roommates of persistently depressed persons displayed a progressive increase in BDI score over the course of the study.     

Interpersonal attraction,social identification and psychological group formation

Two perspectives on the nature of the social group and psychological group formation are discussed. The traditional social cohesion approach traces group formation to processes of interpersonal attraction, while the social identity approach defines the group in cognitive terms and considers identification, or self-categorization, to be the mechanism of psychological group formation. On the basis of an experiment by Turner, Sachdev and Hogg (1983) it is hypothesized that interpersonal attraction (positive or negative) is related to group formation only in so far as it enhances intergroup distinctiveness. This hypothesis is experimentally tested in a 2 × 3 (interpersonal liking/disliking per se versus no explicit categorization/random categorization/criterial categorization on the basis of affect) factorial design employing the ‘minimal group’ paradigm. People who like each other and were not explicitly categorized formed a group. This effect was enhanced by criterial categorization but disappeared when categorization was random. Although the results do not support the hypothesis, they are not explicable in social cohesion terms. A social identity explanation is furnished—attraction influences group formation by acting, under certain specifiable conditions, as a cognitive criterion for common category membership. This explanation is located in current theorizing and is proposed as part of a reconceptualization of the relationship between interpersonal attraction and group formation.     

Preference for decision structures in a social dilemma situation

Additional results from Rutte and Wilke's (1984) study are presented. In the context of a social dilemma situation two variables were manipulated: use and variance. Preference for various decision structures is the issue of the present paper. It appeared that a large majority structure and an unanimity structure were mast preferred. A small majority structure and a structure in which each decides for him/herself were intermediately preferred. Whereas a structure in which one person, a leader, decides for all was least preferred. Further analysis of these data suggested that only the latter two decision structures were influenced by the use and variance manipulations.     

Estimating social and nonsocial utility functions from ordinal data

This paper reports an experiment testing two hypotheses. The first is that the value or utility associated with a payment to one's self and a payment to a co-worker can be represented as an additive function of a utility for own payment (nonsocial utility) and a utility for the difference between own and other's payment (social utility). The second hypothesis is that changes in the amount of work accomplished by one's self and/or the other should influence the social, but not the the nonsocial utilities. Support for both hypotheses is reported.     

Symbolic comparisons with and without perceptual referents: Is interval information used?

In an attempt to investigate the range effect obtained by Moyer and Bayer (1976), two groups of subjects were taught to associate colors with circles that differed in size by larger or smaller intervals and then participated in a symbolic comparison task, in which they determined which of two simultaneously presented symbols (the first letters of two colors) represented the larger magnitude. A third group of subjects, who merely learned an arbitrary ordering of the colors along the dimension of size, also participated in the symbolic comparison task. Despite the fact that no practice trials were given, there was no effect of interval size in either early or late blocks, and the circle-learning groups did not differ in performance from the group who only learned an arbitrary ordering of colors, even when pairs containing end terms were removed from the analysis. It is concluded that subjects do not use analogue codes in symbolic comparison tasks involving small, repeated sets of arbitrarily defined symbols.